The present invention relates to patterning methods for thin films, and more particularly to patterning methods using a die.
Organic light emitting devices (OLEDs), which make use of thin films that emit light when excited by electric current, are becoming an increasingly popular technology for applications such as flat panel displays. Popular OLED configurations include double heterostructure, single heterostructure, and single layer, as described in PCT Application WO 96/19792, which is incorporated herein by reference.
To form an array of OLEDs, the constituent materials must be patterned. Such patterning maybe achieved by photoresist methods, as disclosed by U.S. Pat. No. 5,641,611 to Shieh, and in U.S. Pat. No. 6,013,528 to Burrows et al. Shadow masks may also be used to pattern, as disclosed by co-pending U.S. patent application Ser. No. 09/182,636. Shadow masks must be thick enough to provide mechanical strength and thus, the obtainable resolution of the pattern is limited. Other methods of patterning have been used, such as excimer laser ablation and conformal masks.
While these known patterning methods are acceptable in certain circumstances, a more accurate, faster and less expensive method of patterning is desirable.
The present invention relates to patterning methods for organic devices, and more particularly to patterning methods using a die. A first layer of organic materials is deposited over a substrate, followed by a first electrode layer. A first patterned die having a raised portion is then pressed onto the first electrode layer, such that the raised portion of the first patterned die contacts portions of the first electrode layer. The patterned die is removed, such that the portions of the first electrode layer in contact with the raised portions of the first patterned die are removed. In one embodiment of the invention, a second organic layer is then deposited over the first electrode layer, followed by a second electrode layer. A second patterned die having a raised portion is pressed onto the second electrode layer, such that the raised portion of the second patterned die contacts portions of the second electrode layer. The second patterned die is removed, such that the portions of the second electrode layer in contact with the raised portions of the second patterned die are removed. Preferably the patterned die is coated with an adhesive material such as a metal.